Reinholdt J, Kilian M
J Dent Res. 1987 Feb;66(2):492-7. doi: 10.1177/00220345870660021801.
It has previously been shown that secretory immunoglobulin A (S-IgA) influences the sorption of oral streptococci to hydroxyapatite as well as to cell surfaces. The present experiments demonstrate that bacterial IgA proteases, which cleave S-IgA in the hinge region, are capable of interfering with this mechanism. This result was obtained with an IgA1 specific protease from Haemophilus influenzae and with a protease from Clostridium ramosum that cleaves IgA1 as well as IgA2 of A2m(1) allotype. The modulation of S-IgA-mediated effects by IgA proteases were studied by means of an in vitro method which permits quantitative determination of the sorption of radiolabeled oral bacteria to hydroxyapatite beads. Other authors have suggested that IgA protease-mediated effects may be explained by a strongly reduced antigen-binding capacity of released Fab alpha fragments. Here we present evidence that streptococci, after exposure to specific S-IgA and IgA protease, are coated with Fab alpha fragments.
先前的研究表明，分泌型免疫球蛋白A（S-IgA）会影响口腔链球菌对羟基磷灰石以及细胞表面的吸附。目前的实验表明，能在铰链区切割S-IgA的细菌IgA蛋白酶能够干扰这一机制。这一结果是通过来自流感嗜血杆菌的IgA1特异性蛋白酶以及来自多枝梭菌的一种能切割A2m(1)同种异型IgA1和IgA2的蛋白酶获得的。通过一种体外方法研究了IgA蛋白酶对S-IgA介导效应的调节作用，该方法能够定量测定放射性标记的口腔细菌对羟基磷灰石珠的吸附。其他作者认为，IgA蛋白酶介导的效应可能是由于释放的Fabα片段的抗原结合能力大幅降低所致。在此我们提供证据表明，链球菌在暴露于特异性S-IgA和IgA蛋白酶后，会被Fabα片段所覆盖。
